Optical devices with azimuthal modulator layer

ABSTRACT

An optical device includes a reflector layer having a first surface, a second surface opposite the first surface; a third surface, and a fourth surface opposite the third surface; and a first selective light modulator layer external to the first surface of the reflector layer; in which at least one of the third surface and the fourth surface includes an azimuthal modulator layer. A method of making an optical device is also disclosed.

FIELD OF THE INVENTION

The present disclosure generally relates to articles, such as opticaldevices in the form of foil, sheets, and/or flakes. The optical devicecan include a reflector layer having a first surface, a second surfaceopposite the first surface, a third surface, and a fourth surfaceopposite the third surface; and a first selective light modulator layerexternal to the first surface of the reflector layer; wherein at leastone of the third surface and the fourth surface includes an azimuthalmodulator layer. Methods of making the optical devices are alsodisclosed.

BACKGROUND OF THE INVENTION

Optical attributes of a pigment are based upon the components present inthe pigment. For example, a “white colored” reflector layer, such asthose made with aluminum, will provide a limited color space attributeto a pigment. Additionally, the use of an aluminum reflector layer canrequire the addition of corrosion protection mechanisms, such aspassivation to eliminate the risk of water-induced corrosion of thealuminum. Corrosion can lead to loss of reflector function and formationof hydrogen. Both of these problems can be detrimental to the pigmentand can restrict its use. Further, the use of a “white colored”reflector layer can limit the ability of a pigment to produce a colorflop and/or a color shifting effect.

SUMMARY OF THE INVENTION

In an aspect, there is disclosed an optical device including a reflectorlayer having a first surface, a second surface opposite the firstsurface; a third surface, and a fourth surface opposite the thirdsurface; and a first selective light modulator layer external to thefirst surface of the reflector layer; in which at least one of the thirdsurface and the fourth surface includes an azimuthal modulator layer.

In another aspect, there is disclosed a method for manufacturing anoptical device, comprising: depositing on a substrate a reflector layerhaving a first surface, a second surface opposite the first surface, athird surface, and a fourth surface opposite the third surface;depositing on the first surface of the reflector layer a first selectivelight modulator layer; and providing an azimuthal modulator layer on atleast one of the third surface and the fourth surface of the reflectorlayer.

Additional features and advantages of various embodiments will be setforth, in part, in the description that follows, and will, in part, beapparent from the description, or can be learned by the practice ofvarious embodiments. The objectives and other advantages of variousembodiments will be realized and attained by means of the elements andcombinations particularly pointed out in the description herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure in its several aspects and embodiments can bemore fully understood from the detailed description and the accompanyingdrawings, wherein:

FIG. 1 is a cross-sectional view of an article according to an aspect ofthe present disclosure;

FIG. 2 is a cross-sectional view of an article according to anotheraspect of the present disclosure;

FIG. 3 is a cross-sectional view of an article according to anotheraspect of the present disclosure;

FIG. 4 is a cross-sectional view of an article according to anotheraspect of the present disclosure;

FIG. 5 is a cross-sectional view of an article according to anotheraspect of the present disclosure;

FIG. 6 is a cross-sectional view of an article according to anotheraspect of the present disclosure;

FIG. 7 is a cross-sectional view of an article according to anotheraspect of the present invention;

FIG. 8 is a cross-sectional view of an article according to anotheraspect of the present invention; and

FIG. 9 is a cross sectional view of a liquid coating process showingdeposition of a layer, such as an SLML layer, according to an example ofthe present disclosure.

Throughout this specification and figures like reference numbersidentify like elements.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory only,and are intended to provide an explanation of various embodiments of thepresent teachings. In its broad and varied embodiments, disclosed hereinare articles, such as optical devices, for example, in the form offoils, sheets, and flakes; and a method of manufacturing the article. Inan example, the articles including optical devices, such as pigments,optical taggants, and optical security devices can be manufactured witha simplified construction. The optical devices disclosed herein canexhibit at least one property including, but not limited to, reduceddegradation of a reflector layer, reduced formation of hydrogen on areflector layer, and improved color attributes.

As illustrated in FIG. 1, an article 10, such as an optical device, caninclude a reflector layer 16; and a selective light modulator layer 14external to the reflector layer and deposited using a liquid coatingprocess. In an aspect, the selective light modulator layer 14 can be afirst selective light modulator layer 14 or a second selective lightmodulator layer 14′, as shown in FIG. 2. The reflector layer 16 can be acolored reflector layer 16. The reflector layer 16 can have opensurfaces. The reflector layer 16 can have at least one surface thatincludes an azimuthal modulator layer 12, as shown in FIGS. 3-8.

In an aspect, the article 10 can be in a form of a sheet that can beused on an object or a substrate. In another aspect, the article 10 canbe in a form of a foil or flake. For example, the article 10 can have alamellar shape. In an aspect, the article 10 can be an optical device.In another aspect, a composition can include the optical device and aliquid medium. The composition can be an ink, a varnish, a paint, etc.In another aspect, the article 10 is an optical device in the form of aflake, for example having 100 nm to 100 μm in thickness and 100 nm to 1mm in size. The article 10 can be a color shifting colorant, or can beused as a security feature for currency. Some attributes common to useof the article 10 can include high chromaticity (or strong color), colorchange with respect to viewing angle (also known as goniochromaticity oriridescence), and flop (a specular and metallic appearance that variesin lightness, hue, or chromaticity as the viewing angle varies).Additionally, the article 10 can be metallic in color and cannot exploitinterference to generate color. In particular, the article 10 caninclude an additional feature for adding angle dependent color shiftingeffects. Further, the article 10 can exhibit improved chemicalprotection of exposed metal surfaces, such as the edges of a reflectorlayer 16, but without the need for encapsulating the entire article 10.

Although the Figures illustrate an article 10, such as an opticaldevice, in the form of a sheet, the article 10, such as an opticaldevice can also be in a form of a flake, and/or a foil, according tovarious aspects of the present disclosure. Additionally, although theFigures illustrate specific layers in specific orders, one of ordinaryskill in the art would appreciate that the article 10 can include anynumber of layers in any order. Additionally, the composition of anyparticular layer can be the same or different from the composition ofany other layer. For example, a first selective light modulator layer(SLML) 14 can be the same or different composition than a secondselective light modulator layer (SLML) 14′. Further, the physicalproperties of any particular layer can be the same or different from thephysical properties of any other layer. For example, a first SLML 14 canhave a composition with a first refractive index, but a second SLML 14′in the same article 10 can have a different composition with a differentrefractive index. As another example, a first SLML 14 can have acomposition at a first thickness, but the second SLML 14′ can have thesame composition at a second thickness different from the firstthickness.

As illustrated in FIG. 1, an article 10, such as an optical device, cancomprise a colored reflector layer 16 having a first surface, a secondsurface opposite the first surface, and a third surface; and a selectivelight modulator layer external to the first surface of the coloredreflector layer 16.

A reflector layer 16 can be a wideband reflector, e.g., spectral andLambertian reflector (e.g., white TiO₂). The reflector layer 16 caninclude a metal. The reflector layer 16 can be a colored reflectorlayer. As used herein, “colored reflector layer” includes a coloredmetal, a colored metal alloy, a colored non-metal, and metals chemicallyconverted into a colored compound. The colored reflector layer 16 can bea colored metal or colored metal alloy chosen from copper, gold, silver,and bronze. The colored reflector layer 16 can be a colored non-metalincluding organic materials like polyacetylene, conducting polymers(e.g., polypyrroles, PEDOT, polyanilines), semiconductors, and inorganicmaterials like metal oxides, sulfides, chlorides, fluorides, titanates,zirconates, rare earth-doped CaF2, transition metal-doped SrTiO3 andCaTiO3, iron or sulfur-doped sodalite, and metal coordination complexes.

In an aspect, the reflector layer 16, such as a colored reflector layer,can include a metal that is chemically converted into a coloredcompound. For example, the metal that is chemically converted caninclude aluminum, stainless steel, and white-colored materials. In anaspect, the metal to be chemically converted can include, but is notlimited to, aluminum, copper, stainless steel, silver, gold, zinc, iron,bronzes, manganese, titanium, zirconium, vanadium, niobium, chromium,molybdenum, nickel, tungsten, tin, indium, bismuth, alloys of any ofthese metals, or a combination thereof. The conversion process can beany process that converts a non-colored or white colored metal to acolored compound. The conversion process can include subjecting anon-colored or white colored metal to a reactant.

The reactant can be in any state, such as plasma state, gas state, solidstate, or liquid state or a combination thereof. The reactant caninclude any chemical or physical factors that can cause a reaction withat least a part of the non-colored or white colored metal, in acontrollable manner. In one example, a water and solvent-borneenvironment can be used as the reactant. In some examples, theconversion process can include the use of various types of chemicalreactants, including batch and continuous stirred tank reactants,tubular reactants, tumbling bed reactants, fluidized bed reactants,continuous flow tube and batch furnaces.

The chemical bath composition used herein can include an inorganiccompound or an organic compound. An example of an inorganic compound caninclude at least one of sulfur, sulfides, sulfates, oxides, hydroxides,isocyanates, thiocyanates, molybdates, chromates, permanganates,carbonates, thiosulfates, colloidal metals, inorganic salts, andmixtures thereof. An example of an organic compound can include anorganic compound that contains sulfur, such as thiols, thioamine,oxythio amines, thiourea, thiocyanates; nitrogen, such as amines, andisocyanates; oxygen; silicon, such as silanes; or a combination thereof.Further, the chemical bath can include at least one of inorganic ororganic salts of metals or metallic organic compounds of metals. In yetanother aspect, the chemical bath can include an oxidizing agent, asurface modifier, and/or an inhibitor.

In an aspect, the non-colored or white colored metal present in areflector layer 16 can be completely converted or partially converted,such as 99.9% converted, including all ranges of percent conversion inbetween.

In an aspect, the colored reflector layer 16 does not include aluminumor a white-colored material, for example, aluminum or a white-coloredmaterial that has not been chemically converted into a colored compound.

In one example, the materials for the reflector layer 16 can include anymaterials that have reflective characteristics in the desired spectralrange. For example, any material with a reflectance ranging from 5% to100% in the desired spectral range.

The thickness of the reflector layer 16 can range from about 5 nm toabout 5000 nm, although this range should not be taken as restrictive.For example, the lower thickness limit can be selected so that thereflector layer 16 can provide a maximum transmittance of 0.8.

In order to obtain a sufficient optical density and/or achieve a desiredeffect, a higher or lower minimum thicknesses can be required dependingof the composition of the reflector layer 16. In some examples, theupper limit can be about 5000 nm, about 4000 nm, about 3000 nm, about1500 nm, about 200 nm, and/or about 100 nm. In one aspect, the thicknessof the reflector layer 16 can range from about 10 nm to about 5000 nmfor example, from about 15 nm to about 4000 nm, from about 20 nm toabout 3000 nm, from about 25 nm to about 2000 nm, from about 30 nm toabout 1000 nm, from about 40 nm to about 750 nm, or from about 50 nm toabout 500 nm, such as from about 60 nm to about 250 nm or from about 70nm to about 200 nm.

As shown in the Figures, for example FIG. 1, at least two surfaces/sidesof the reflector layer 16, for example, the right (third) and left(fourth) surface/side as shown, can be open. In an aspect, if thearticle 10 is in the form of a flake or foil, then reflector layer 16can include more than the four surfaces exemplified in the Figures. Inthose instances, for example, one, two, three, four, or five surfaces ofthe reflector layer 16 can be open to the air. In an example, opensides, i.e., surfaces of the reflector layer 16 that do not contain anexternal layer, can be an advantage for flop. In another aspect, asshown in FIGS. 7 and 8, the article 10 can include a reflector layer 16and/or a SLML layer 14 that is not open, i.e., that have an azimuthallayer 12, 12′ external to a side surface, such as side surface of thereflector layer 16 and/or the SLML layer 14. In another aspect, anysurface of the reflector layer 16, the SLML 14, and/or the azimuthallayer 12 can also include a functional layer (not shown) includingfunctional molecules.

In an aspect, the article 10, such as an optical device, can include areflector layer 16, such as a colored reflector layer, having a firstcolor; and the selective light modulator layer 14 has a second color thesame as the first color, as shown in FIG. 1. For example, the reflectorlayer 16 can be red and the selective light modulator layer can also bered.

In another aspect, the article 10, such as an optical device, caninclude a reflector layer 16, such as a colored reflector layer, havinga first color; and the selective light modulator layer 14 has a secondcolor that is different from the first color, also as shown in FIG. 1.For example, the reflector layer 16 can be red and the selective lightmodulator layer 14 can be blue.

The article 10, such as an optical device, can include a selective lightmodulator layer 14 that is a first selective light modulator layer 14;and can further include a second selective light modulator layer 14′.The first selective light modulator layer 14 is present on a firstsurface of the reflector layer 16 and the second selective lightmodulator layer 14′ is present on a second surface of the reflectorlayer 16, as shown in FIG. 2. Each of the first and second selectivelight modulator layer 14, 14′ can have the same or different color.Additionally, the reflector layer 16 can be a colored reflector layer 16that has the same or different color than each of the first and secondselective light modulator layer 14, 14′. For example, the firstselective light modulator layer 14 can be a second color red, thereflector layer can be a first color blue, and the second selectivelight modulator layer 14′ can be red. In another aspect, the firstselective light modulator layer 14 can be a second color red, thereflector layer can include copper and can be a first color red (perhapshaving a different hue), and the second selective light modulator layer14′ can be red. In a further aspect, the first selective light modulatorlayer 14 can be a second color red, the reflector layer can be a firstcolor blue, and the second selective light modulator layer 14′ can beyellow.

The article 10, as shown in FIGS. 3-8, can exhibit a metallic effectbecause the edges of the article, such as a flake or an optical device,can act as a secondary color defining feature, such as an azimuthalcolor attribute. In an aspect, the article 10 can include a reflectorlayer 16 having a first surface, a second surface opposite the firstsurface, a third surface, and a fourth surface opposite the thirdsurface; and a first selective light modulator layer 14 external to thefirst surface of the reflector layer 16; wherein at least one of thethird surface and the fourth surface of the reflector layer 16 includesan azimuthal modulator layer 12. The article 10 can further include asecond selective light modulator layer 14′ external to the secondsurface of the reflector layer 16. The reflector layer 16 can be asdescribed above. The first selective light modulator layer 14, secondselective light modulator layer 14′, first azimuthal modulator layer 12,and second azimuthal modulator layer 12′ can be as described below.

The first selective light modulator layer 14 can provide a first colorattribute to the article 10, such as an optical device. For example, thefirst selective modulator layer 14 can provide a red color to theoptical device. The first color attribute can be present at a firstviewing angle.

The azimuthal modulator layer 12, 12′ can provide a second colorattribute to the article 10, such as the optical device. For example,the azimuthal modulator layer 12, 12′ can provide a black color to theoptical device. The second color attribute can be present at a secondviewing angle, wherein the second viewing angle is different from thefirst viewing angle. The second color attribute can be different from afirst color attribute. The azimuthal modulator layer 12, 12′ can allowthe introduction of color hue to the article 10, such as visible fromviewing angles other than normal, to articles 10 that can have theirfirst color attribute defined by the selective light modulator layer 14.

As shown in FIG. 3, the article 10 can include a reflector layer 16; aselective light modulator layer 14 external to a first surface of thereflector layer 16; and an azimuthal modulator layer 12 external to athird surface of the reflector layer 16. In an aspect, the azimuthalmodulator layer 12 can protect at least one of the third surface and thefourth surface of the reflector layer 16. A second surface opposite thefirst surface and a fourth surface opposite the third surface of thereflector layer 16 can be open to the air. The reflector layer 16 can beas described above. In an aspect, the reflector layer 16 can include acolored material.

As shown in FIG. 4, the article 10 can include a reflector layer 16; afirst selective light modulator layer 14 external to a first surface ofthe reflector layer 16; a second light selective light modulator layer14′ external to the second surface of the reflector layer 16; and anazimuthal modulator layer 12 external to a third surface of thereflector layer 16. In an aspect, the azimuthal modulator layer 12 canprotect at least one of the third surface and the fourth surface of thereflector layer 16. A fourth surface opposite the third surface of thereflector layer 16 can be open to the air. The reflector layer 16 can beas described above. In an aspect, the reflector layer 16 can include acolored material.

As shown in FIG. 5, the article 10 can include a reflector layer 16; afirst selective light modulator layer 14 external to a first surface ofthe reflector layer 16; a first azimuthal modulator layer 12 external toa third surface of the reflector layer 16; and a second azimuthalmodulator layer 12′ external to a fourth surface of the reflector layer16. In an aspect, at least one of the first and second azimuthalmodulator layer 12, 12′ can protect at least one of the third surfaceand the fourth surface of the reflector layer 16. A second surfaceopposite the first surface of the reflector layer 16 can be open to theair. The reflector layer 16 can be as described above. In an aspect, thereflector layer 16 can include a colored material.

As shown in FIG. 6, the article 10 can include a reflector layer 16; afirst selective light modulator layer 14 external to a first surface ofthe reflector layer 16; a second selective light modulator layer 14′external to a second surface of the reflector layer 16; a firstazimuthal modulator layer 12 external to a third surface of thereflector layer 16; and a second azimuthal modulator layer 12′ externalto a fourth surface of the reflector layer 16. In an aspect, at leastone of the first and second azimuthal modulator layer 12, 12′ canprotect at least one of the third surface and the fourth surface of thereflector layer 16. The reflector layer 16 can be as described above. Inan aspect, the reflector layer 16 can include a colored material.

As shown in FIG. 7, the article 10 can include a reflector layer 16; afirst selective light modulator layer 14 external to a first surface ofthe reflector layer 16; a first azimuthal modulator layer 12 external toa third surface of the reflector layer 16 and external to a thirdsurface of the first selective light modulator layer 14; and a secondazimuthal modulator layer 12′ external to a fourth surface of thereflector layer 16 and external to a fourth surface of the firstselective light modulator layer 14. The first selective light modulatorlayer 14 can have a first surface; a second surface opposite the firstsurface; a third surface; and a fourth surface opposite the thirdsurface. In an aspect, at least one of the first and second azimuthalmodulator layer 12, 12′ can protect at least one of the third surface ofthe reflector layer 16, the fourth surface of the reflector layer 16,the third surface of the first selective light modulator layer 14, andthe fourth surface of the first selective light modulator layer 14. Thereflector layer 16 can be as described above. In an aspect, thereflector layer 16 can include a colored material.

As shown in FIG. 8, the article 10 can include a reflector layer 16; afirst selective light modulator layer 14 external to a first surface ofthe reflector layer 16; a second selective light modulator layer 14′external to a second surface of the reflector layer 16; a firstazimuthal modulator layer 12 external to a third surface of thereflector layer 16, external to a third surface of the first selectivelight modulator layer 14, and external to a third surface of the secondselective light modulator layer 14′; and a second azimuthal modulatorlayer 12′ external to a fourth surface of the reflector layer 16,external to a fourth surface of the first selective light modulatorlayer 14, and external to a fourth surface of the second selective lightmodulator layer 14′. The first and second selective light modulatorlayer 14, 14′ can each independently have a first surface; a secondsurface opposite the first surface; a third surface; and a fourthsurface opposite the third surface. In an aspect, at least one of thefirst and second azimuthal modulator layer 12, 12′ can protect at leastone of the third surface of the reflector layer 16, the fourth surfaceof the reflector layer 16, the third surface of the first selectivelight modulator layer 14, the fourth surface of the first selectivelight modulator layer 14, the third surface of the second selectivelight modulator layer 14′, and the fourth surface of the secondselective light modulator layer 14′. The reflector layer 16 can be asdescribed above. In an aspect, the reflector layer 16 can include acolored material.

With regard to FIGS. 3-8, the azimuthal modulator layer 12, 12′ caninclude a metal chemically converted to a colored compound, as disclosedabove with regard to the reflector layer 16. In an aspect, the azimuthalmodulator layer 12, 12′ can also include at least one of pigments andorganic dyes. The azimuthal modulator layer 12, 12′ can protect thesurfaces of the article 10 from corrosion.

The article 10 disclosed herein can include a first selective lightmodulator layer (SLML) 14 and/or a second selective light modulatorlayer 14′. The SLML is a physical layer comprising a plurality ofoptical functions aiming at modulating (absorbing and or emitting) lightintensity in different, selected regions of spectrum of electromagneticradiation with wavelengths ranging from about 0.2 μm to about 20 μm. Thearticle 10 can include an asymmetric layer structure in which the SLML14 can selectively modulate light by means of absorption provided by aselective SLMS (discussed in more detail below). In particular, thearticle 10 can include a SLML 14 that selectively absorbs specificwavelengths of energy, such as light.

A SLML 14 (and/or the materials within the SLML 14) can selectivelymodulate light. For example, an SLML 14 can control the amount oftransmission in specific wavelengths. In some examples, the SLML 14 canselectively absorb specific wavelengths of energy (e.g., in the visibleand/or non-visible ranges). For example, the SLML 14 can be a “coloredlayer” and/or a “wavelength selective absorbing layer.” In someexamples, the specific wavelengths absorbed can cause the article 10 toappear a specific color. For example, the SLML 14 can appear red to thehuman eye (e.g., the SLML 14 can absorb wavelengths of light belowapproximately 620 nm and thus reflect or transmit wavelengths of energythat appear red). This can be accomplished by adding selective lightmodulator particles (SLMP) that are colorants (e.g., organic and/orinorganic pigments and/or dyes) to a host material, such as a dielectricmaterial, including but not limited to a polymer. For example, in someinstances, the SLML 14 can be a colored plastic.

In some examples, some or all of the specific wavelengths absorbed canbe in the visible range (e.g., the SLML 14 can be absorbing throughoutthe visible, but transparent in the infrared). The resulting article 10would appear black, but reflect light in the infrared. In some examplesdescribed above, the wavelengths absorbed (and/or the specific visiblecolor) of the article 10 and/or SLML 14 can depend, at least in part, onthe thickness of the SLML 14. Additionally, or alternatively, thewavelengths of energy absorbed by the SLML 14 (and/or the color in whichthese layers and/or the flake appears) can depend in part on theaddition of certain aspects to the SLML 14. In addition to absorbingcertain wavelengths of energy, the SLML 14 can achieve at least one ofbolstering the reflector layer 16 against degradation; enabling releasefrom a substrate; enabling sizing; providing some resistance toenvironmental degradation, such as oxidation of aluminum or other metalsand materials used in the reflector layer 16; and high performance intransmission, reflection, and absorption of light based upon thecomposition and thickness of the SLML 14.

In some examples, in addition to or as an alternative to the SLML 14selectively absorbing specific wavelengths of energy and/or wavelengthsof visible light, the SLML 14 of the article 10 can control therefractive index and/or the SLML 14 can include selective lightmodulator particles (SLMPs) that can control refractive index. SLMPsthat can control the refractive index of the SLML 14 can be includedwith the host material in addition to or as an alternative to anabsorption controlling SLMPs (e.g., colorants). In some examples, thehost material can be combined with both absorption controlling SLMPs andrefractive index SLMPs in the SLML 14. In some examples, the same SLMPcan control both absorption and refractive index.

The performance of the SLML 14 can be determined based upon theselection of materials present in the SLML 14. In an aspect, the SLML 14can improve at least one of the following properties: flake handling,corrosion, alignment, and environmental performance of any other layerswithin article 10, e.g., the reflector layer 16.

The first and (optionally second, third, fourth, etc.) SLML 14 can eachindependently comprise a host material alone, or a host materialcombined with a selective light modulator system (SLMS). In an aspect,at least one of the first SLML 14 can include a host material. Inanother aspect, at least one of the first SLML 14 can include a hostmaterial and a SLMS. The SLMS can include a selective light modulatormolecule (SLMM), a selective light modulator particle (SLMP), anadditive, or combinations thereof.

The composition of the SLML 14 can have a solids content ranging fromabout 0.01% to about 100%, for example from about 0.05% to about 80%,and as a further example from about 1% to about 30%. In some aspects,the solids content can be greater than 3%. In some aspects, thecomposition of the SLML 14 can have a solids content ranging from about3% to about 100%, for example from about 4% to 50%.

The host material of the first SLML 14 can independently be a filmforming material applied as a coating liquid and serving optical andstructural purposes. The host material can be used as a host (matrix)for introducing, if necessary, a guest system, such as the selectivelight modulator system (SLMS), for providing additional light modulatorproperties to the article 10.

The host material can be a dielectric material. Additionally, oralternatively, the host material can be at least one of an organicpolymer, an inorganic polymer, and a composite material. Non-limitingexamples of the organic polymer include thermoplastics, such aspolyesters, polyolefins, polycarbonates, polyamides, polyimides,polyurethanes, acrylics, acrylates, polyvinylesters, polyethers,polythiols, silicones, fluorocarbons, and various co-polymers thereof;thermosets, such as epoxies, polyurethanes, acrylates, melamineformaldehyde, urea formaldehyde, and phenol formaldehyde; and energycurable materials, such as acrylates, epoxies, vinyls, vinyl esters,styrenes, and silanes. Non-limiting examples of inorganic polymersincludes silanes, siloxanes, titanates, zirconates, aluminates,silicates, phosphazanes, polyborazylenes, and polythiazyls.

The first SLML 14 can include from about 0.001% to about 100% by weightof a host material. In an aspect, the host material can be present inthe SLML 14 in an amount ranging from about 0.01% to about 95% byweight, for example from about 0.1% to about 90%, and as a furtherexample from about 1% to about 87% by weight of the SLML 14.

The SLMS, for use in the SLML 14 with the host material, can eachindependently comprise selective light modulator particles (SLMP),selective light modulator molecules (SLMM), additives, or a combinationthereof. The SLMS can also comprise other materials. The SLMS canprovide modulation of the amplitude of electromagnetic radiation (byabsorption, reflectance, fluorescence etc.) in a selective region or theentire spectral range of interest (0.2 μm to 20 μm).

The first SLML 14 can each independently include in an SLMS a SLMP. TheSLMP can be any particle combined with the host material to selectivelycontrol light modulation, including, but not limited to color shiftingparticles, dyes, colorants include colorant includes one or more ofdyes, pigments, reflective pigments, color shifting pigments, quantumdots, and selective reflectors. Non-limiting examples of a SLMP include:organic pigments, inorganic pigments, quantum dots, nanoparticles(selectively reflecting and/or absorbing), micelles, etc. Thenanoparticles can include, but are not limited to organic andmetalorganic materials having a high value of refractive index (n>1.6 atwavelength of about 550 nm); metal oxides, such as TiO₂, ZrO₂, In₂O₃,In₂O₃—SnO, SnO₂, Fe_(x)O_(y) (wherein x and y are each independentlyintegers greater than 0), and WO₃; metal sulfides, such as ZnS, andCu_(x)S_(y) (wherein x and y are each independently integers greaterthan 0); chalcogenides, quantum dots, metal nanoparticles; carbonates;fluorides; and mixtures thereof.

Examples of a SLMM include but are not limited to: organic dyes,inorganic dyes, micelles, and other molecular systems containing achromophore.

In some aspects, SLMS of the first SLML 14 can include at least oneadditive, such as a curing agent, and a coating aid.

The curing agent can be a compound or material that can initiatehardening, vitrification, crosslinking, or polymerizing of the hostmaterial. Non-limiting examples of a curing agent include solvents,radical generators (by energy or chemical), acid generators (by energyor chemical), condensation initiators, and acid/base catalysts.

Non-limiting examples of the coating aid include leveling agents,wetting agents, defoamers, adhesion promoters, antioxidants, UVstabilizers, curing inhibition mitigating agents, antifouling agents,corrosion inhibitors, photosensitizers, secondary crosslinkers, andinfrared absorbers for enhanced infrared drying. In an aspect, theantioxidant can be present in the composition of the SLML 14 in anamount ranging from about 25 ppm to about 5% by weight.

The first SLML 14 can each independently comprise a solvent.Non-limiting examples of solvents can include acetates, such as ethylacetate, propyl acetate, and butyl acetate; acetone; water; ketones,such as dimethyl ketone (DMK), methylethyl ketone (MEK), secbutyl methylketone (SBMK), ter-butyl methyl ketone (TBMK), cyclopenthanon, andanisole; glycol and glycol derivatives, such as propylene glycol methylether, and propylene glycol methyl ether acetate; alcohols, such asisopropyl alcohol, and diacetone alcohol; esters, such as malonates;heterocyclic solvents, such as n-methyl pyrrolidone; hydrocarbons, suchas toluene, and xylene; coalescing solvents, such as glycol ethers; andmixtures thereof. In an aspect, the solvent can be present in the firstSLML 14′ in an amount ranging from about 0% to about 99.9%, for examplefrom about 0.005% to about 99%, and as a further example from about0.05% to about 90% by weight relative to the total weight of the SLML14.

In some examples, the first SLML 14 can include a composition having atleast one of (i) a photoinitiator, (ii) an oxygen inhibition mitigationcomposition, (iii) a leveling agent, and (iv) a defoamer.

The oxygen inhibition mitigation composition can be used to mitigate theoxygen inhibition of the free radical material. The molecular oxygen canquench the triplet state of a photoinitiator sensitizer or it canscavenge the free radicals resulting in reduced coating propertiesand/or uncured liquid surfaces. The oxygen inhibition mitigationcomposition can reduce the oxygen inhibition or can improve the cure ofany SLML 14.

The oxygen inhibition composition can comprise more than one compound.The oxygen inhibition mitigation composition can comprise at least oneacrylate, for example at least one acrylate monomer and at least oneacrylate oligomer. In an aspect, the oxygen inhibition mitigationcomposition can comprise at least one acrylate monomer and two acrylateoligomers. Non-limiting examples of an acrylate for use in the oxygeninhibition mitigation composition can include acrylates; methacrylates;epoxy acrylates, such as modified epoxy acrylate; polyester acrylates,such as acid functional polyester acrylates, tetra functional polyesteracrylates, modified polyester acrylates, and bio-sourced polyesteracrylates; polyether acrylates, such as amine modified polyetheracrylates including amine functional acrylate co-initiators and tertiaryamine co-initiators; urethane acrylates, such aromatic urethaneacrylates, modified aliphatic urethane acrylates, aliphatic urethaneacrylates, and aliphatic allophanate based urethane acrylates; andmonomers and oligomers thereof. In an aspect, the oxygen inhibitionmitigation composition can include at least one acrylate oligomer, suchas two oligomers. The at least one acrylate oligomer can beselected/chosen from a polyester acrylate and a polyether acrylate, suchas a mercapto modified polyester acrylate and an amine modifiedpolyether tetraacrylate. The oxygen inhibition mitigation compositioncan also include at least one monomer, such as 1,6-hexanedioldiacrylate. The oxygen inhibition mitigation composition can be presentin the first SLML 14 in an amount ranging from about 5% to about 95%,for example from about 10% to about 90%, and as a further example fromabout 15% to about 85% by weight relative to the total weight of theSLML 14.

In some examples, the host material of the SLML 14 can use a non-radicalcure system such as a cationic system. Cationic systems are lesssusceptible to the mitigation of the oxygen inhibition of the freeradical process, and thus may not require an oxygen inhibitionmitigation composition. In an example, the use of the monomer3-ethyl-3-hydroxymethyloxetane does not require an oxygen mitigationcomposition.

In an aspect, the first SLML 14 can each independently include at leastone photoinitiator, such as two photoinitiators, or threephotoinitiators. The photoinitiator can be used for shorter wavelengths.The photoinitiator can be active for actinic wavelength. Thephotoinitiator can be a Type 1 photoinitiator or a Type IIphotoinitiator. The SLML 14 can include only Type I photoinitiators,only Type II photoinitiators, or a combination of both Type I and TypeII photoinitiators. The photoinitiator can be present in the compositionof the SLML 14 in an amount ranging from about 0.25% to about 15%, forexample from about 0.5% to about 10%, and as a further example fromabout 1% to about 5% by weight relative to the total weight of thecomposition of the SLML 14.

The photoinitiator can be a phosphineoxide. The phosphineoxide caninclude, but is not limited to, a monoacyl phosphineoxide and a bis acylphosphine oxide. The mono acyl phosphine oxide can be a diphenyl(2,4,6-trimethylbenzoyl)phosphineoxide. The bis acyl phosphine oxide canbe a bis (2,4,6-trimethylbenzoyl)phenylphosphineoxide. In an aspect, atleast one phosphineoxide can be present in the composition of the SLML14. For example, two phosphineoxides can be present in the compositionof the SLML 14.

A sensitizer can be present in the composition of the SLML 14 and canact as a sensitizer for Type 1 and/or a Type II photoinitiators. Thesensitizer can also act as a Type II photoinitiator. In an aspect, thesensitizer can be present in the composition of the SLML 14 in an amountranging from about 0.05% to about 10%, for example from about 0.1% toabout 7%, and as a further example from about 1% to about 5% by weightrelative to the total weight of the composition of the SLML 14. Thesensitizer can be a thioxanthone, such as1-chloro-4-propoxythioxanthone.

In an aspect, the SLML 14 can include a leveling agent. The levelingagent can be a polyacrylate. The leveling agent can eliminate crateringof the composition of the SLML 14. The leveling agent can be present inthe composition of the SLML 14 in an amount ranging from about 0.05% toabout 10%, for example from about 1% to about 7%, and as a furtherexample from about 2% to about 5% by weight relative to the total weightof the composition of the SLML 14.

The first SLML 14 can also include a defoamer. The defoamer can reducesurface tension. The defoamer can be a silicone free liquid organicpolymer. The defoamer can be present in the composition of the SLML 14in an amount ranging from about 0.05% to about 5%, for example fromabout 0.2% to about 4%, and as a further example from about 0.4% toabout 3% by weight relative to the total weight of the composition ofthe SLML 14.

The first SLML 14 can each independently have a refractive index ofgreater or less than about 1.5. For example, each SLML 14′ can have arefractive index of approximately 1.5. The refractive index of each SLML14 can be selected to provide a degree of color travel required whereincolor travel can be defined as the change in hue angle measured inL*a*b* color space with the viewing angle. In some examples, each SLML14 can include a refractive index in a range of from about 1.1 to about3.0, about 1.0 to about 1.3, or about 1.1 to about 1.2. In someexamples, the refractive index of each SLMLs 14 can be less than about1.5, less than about 1.3, or less than about 1.2. In some examples, SLML14 can have substantially equal refractive indexes or differentrefractive indexes one from the other, if more than one SLML is presentin the article 10.

The first SLML 14 can have a thickness ranging from about 1 nm to about10000 nm, about 10 nm to about 1000 nm, about 20 nm to about 500 nm,about 1 nm, to about 100 nm, about 10 nm to about 1000 nm, about 1 nm toabout 5000 nm. In an aspect, the article 10, such as an optical device,can have an aspect ratio of 1:1 to 1:50 thickness to width.

One of the benefits of the articles 10 described herein, however, isthat, in some examples, the optical effects appear relativelyinsensitive to thickness variations. Thus, in some aspects, each SLML 14can independently have a variation in optical thickness of less thanabout 5%. In an aspect, each SLML 14 can independently include anoptical thickness variation of less than about 3% across the layer. Inan aspect, each SLML 14 can independently have less than about 1%variation in optical thickness across the layer having a thickness ofabout 50 nm.

In an aspect, the article 10, such as an optical device in the form of aflake, foil or sheet, can also include a substrate and/or a releaselayer. In an aspect, the release layer can be disposed between thesubstrate and the article 10.

Additionally, or alternatively, the article 10 in the form of a flake,sheet, or foil can also include a hard coat or protective layer on thearticle 10. In some examples, these layers (hard coat or protectivelayer) do not require optical qualities.

The article 10, such as optical devices, described herein can be made inany way. For example, a sheet can be made and then divided, broken,ground, etc. into smaller pieces forming an optical device. In someexamples, the sheet can be created by a liquid coating process,including, but not limited the processes described below and/or withrespect to FIG. 9.

There is disclosed a method for manufacturing an article 10, for examplein the form of a sheet, flake, or foil, as described herein. The methodcan comprise depositing on a substrate a colored reflector layer 16;depositing a selective light modulator layer 14 onto the coloredreflector layer 16 using a liquid coating process. The selective lightmodulator layer 14 can be a first selective light modulator layer, andthe method can further include depositing a second selective lightmodulator layer 14′ between the substrate and the colored reflectorlayer 16.

The colored reflector layer 16 is not subjected to passivation. Thecolored reflector layer can improve a color attribute of the selectivelight modulator layer 14. The colored reflector layer 16 can controlgassing. The colored reflector layer 16 can be deposited using aphysical vapor deposition process. The colored reflector layer 16 caninclude a colored metal, colored metal alloys, colored non-metals, andmetals chemically converted into a colored compound. The coloredreflector layer 16 can be a colored metal chosen from copper, gold, andbronzes. The metals that are chemically converted into a coloredcompound include aluminum and stainless steel. The colored reflectorlayer 16 can include a colored non-metal including polyacetylene andorganic materials.

In another aspect, there is disclosed a method of making an article 10,such as an optical device, including depositing on a substrate areflector layer 16 having a first surface, a second surface opposite thefirst surface, a third surface, and a fourth surface opposite the thirdsurface; depositing on the first surface of the reflector layer 16 afirst selective light modulator layer 14; and providing an azimuthalmodulator layer 12 on at least one of the third surface and the fourthsurface of the reflector layer 16. The method can also includedepositing a second selective light modulator layer 14′ between thesubstrate and the reflector layer 16. The azimuthal modulator layer 12,12′ can inhibit corrosion of the reflector layer 16. The first andsecond selective light modulator layer 14, 14′ can provide a first colorattribute and the azimuthal modulator layer 12, 12′ can provide a secondcolor attribute different from the first color attribute. The azimuthalmodulator layer 12, 12′ can include a chemically converted portion ofthe reflector layer 16. The azimuthal modulator layer 12, 12′ caninclude pigments and organic dyes.

In the methods, the substrate can comprise a release layer. In thedisclosed methods, the reflector layer 16 can be deposited using knownconventional deposition process, such as physical vapor deposition,chemical vapor deposition, thin-film deposition, atomic layerdeposition, etc., including modified techniques such as plasma enhancedand fluidized bed.

The substrate can be made of a flexible material. The substrate can beany suitable material that can receive the deposited layers.Non-limiting examples of suitable substrate materials include polymerweb, such as polyethylene terephthalate (PET), glass foil, glass sheets,polymeric foils, polymeric sheets, metal foils, metal sheets, ceramicfoils, ceramic sheets, ionic liquid, paper, silicon wafers, etc. Thesubstrate can vary in thickness, but can range for example from about 2μm to about 100 μm, and as a further example from about 10 to about 50μm.

The first and/or second SLML 14, 14′ can be deposited by a liquidcoating process, such as a slot die process. The liquid coating processcan include, but is not limited to: slot-bead, slide bead, slot curtain,slide curtain, in single and multilayer coating, tensioned web slot,gravure, roll coating, and other liquid coating and printing processesthat apply a liquid on to a substrate or previously deposited layer toform a liquid layer or film that is subsequently dried and/or cured.

The substrate can then be released from the deposited layers to createthe article 10. In an aspect, the substrate can be cooled to embrittlean associated release layer, if present. In another aspect, the releaselayer could be embrittled for example by heating and/or curing withphotonic or e-beam energy, to increase the degree of cross-linking,which would enable stripping. The deposited layers can then be strippedmechanically, such as sharp bending or brushing of the surface. Thereleased and stripped layers can be sized into article 10, such as anoptical device in the form of a flake, foil, or sheet, using knowntechniques.

In another aspect, the deposited layers can be transferred from thesubstrate to another surface. The deposited layers can be punched or cutto produce large flakes with well-defined sizes and shapes.

The liquid coating process can allow for the transfer of the compositionof the SLML 14, 14′ at a faster rate as compared to other depositiontechniques, such as vapor deposition. Additionally, the liquid coatingprocess can allow for a wider variety of materials to be used in theSLML 14, 14′ with a simple equipment set up. It is believed that theSLML 14, 14′ formed using the disclosed liquid coating process canexhibit improved optical performance.

FIG. 9 illustrates the formation of a layer using a liquid coatingprocess. The composition of a layer, e.g. SLML 14 (a liquid coatingcomposition) can be inserted into a slot die 320 and deposited on asubstrate 340 resulting in a wet film. With reference to the processesdisclosed above, the substrate 340 can include at least one of asubstrate, a release layer, a reflector layer 16, and previouslydeposited layers. The distance from the bottom of the slot die 320 tothe substrate 340 is the slot gap G. As can be seen in FIG. 9, theliquid coating composition can be deposited at a wet film thickness Dthat is greater than a dry film thickness H. After the wet film of theliquid coating composition has been deposited on the substrate 340, anysolvent present in the wet film of the liquid coating composition can beevaporated. The liquid coating process continues with curing of the wetfilm of the liquid coating composition to result in a cured,self-leveled layer having the correct optical thickness H (ranging fromabout 30 to about 700 nm). It is believed that the ability of the liquidcoating composition to self-level results in a layer having a reducedoptical thickness variation across the layer. Ultimately, an article 10,such as an optical device, comprising the self-leveled liquid coatingcomposition can exhibit increased optical precision. For ease ofunderstanding, the terms “wet film” and “dry film” will be used to referto the liquid coating composition at various stages of the liquidcoating process.

The liquid coating process can comprise adjusting at least one of acoating speed and a slot gap G to achieve a wet film with apredetermined thickness D. The liquid coating composition can bedeposited having a wet film thickness D ranging from about 0.1 μm toabout 500 μm, for example from about 0.1 μm to about 5 μm. The liquidcoating composition formed with a wet film thickness D in the disclosedrange can result in a stable SLML layer, such as a dielectric layer,i.e., without breaks or defects such as ribbing or streaks. In anaspect, the wet film can have a thickness of about 10 μm for a stablewet film using a slot die bead mode with a coating speed up to about 100m/min. In another aspect, the wet film can have a thickness of about 6-7μm for a stable wet film using a slot die curtain mode with a coatingspeed up to about 1200 m/min.

The liquid coating process can include a ratio of slot gap G to wet filmthickness D of about 1 to about 100 at speeds from about 0.1 to about1000 m/min. In an aspect, the ratio is about 9 at a coating speed ofabout 100 m/min. In an aspect, the ratio can be about 20 at a coatingspeed of about 50 m/min. The liquid coating process can have a slot gapG ranging from about 0 to about 1000 μm. A smaller slot gap G can allowfor a reduced wet film thickness. In slot-bead mode higher coatingspeeds can be achieved with a wet film thickness greater than 10 μm.

The liquid coating process can have a coating speed ranging from about0.1 to about 1000 m/min, for example from about 25 m/min to about 950m/min, for example from about 100 m/min to about 900 m/min, and as afurther example from about 200 m/min to about 850 m/min. In an aspect,the coating speed is greater than about 150 m/min, and in a furtherexample is greater than about 500 m/min.

In an aspect, the coating speed for a bead mode liquid coating processcan range from about 0.1 m/min to about 600 m/min, and for example fromabout 50 to about 150 m/min. In another aspect, the coating speed for acurtain mode liquid coating process can range from about 200 m/min toabout 1500 m/min, and for example, from about 300 m/min to about 1200m/min.

As shown in FIG. 9 the solvent can be evaporated from the wet film, suchas before the wet film is cured. In an aspect, about 100%, for exampleabout 99.9%, and as a further example about 99.8% of the solvent can beevaporated from the liquid coating composition prior to curing of theliquid coating composition. In a further aspect, trace amounts ofsolvent can be present in a cured/dry liquid coating composition. In anaspect, a wet film having a greater original weight percent of solventcan result in a dry film having a reduced film thickness H. Inparticular, a wet film having a high weight percent of solvent and beingdeposited at a high wet film thickness D can result in a liquid coatingcomposition, such as the SLML 14 having a low dry film thickness H. Itis important to note, that after evaporation of the solvent, the wetfilm remains a liquid thereby avoiding problems such as skinning, andisland formation during the subsequent curing steps in the liquidcoating process.

The dynamic viscosity of the wet film can range from about 0.5 to about50 cP, for example from about 1 to about 45 cP, and as a further examplefrom about 2 to about 40 cP. The viscosity measurement temperature is25° C., the rheology was measured with an Anton Paar MCR 101 rheometerequipped with a solvent trap using a cone/plate 40 mm diameter with 0.3°angle at a gap setting of 0.025 mm.

In an aspect, the liquid coating composition and the solvent can beselected so that the wet film exhibits Newtonian behavior for precisioncoating of the liquid coating composition using the liquid coatingprocess. The wet film can exhibit Newtonian behavior shear rates up to10,000 s⁻¹ and higher. In an aspect, the shear rate for the liquidcoating process can be 1000 s⁻¹ for a coating speed up to 25 m/min, forexample 3900 s⁻¹ for a coating speed up to 100 m/min, and as a furtherexample 7900 s⁻¹ for a coating speed up to 200 m/min. It will beunderstood that a maximum shear rate can occur on a very thin wet film,such as 1 μm thick.

As the wet film thickness is increased, the shear rate can be expectedto decrease, for example decrease 15% for a 10 μm wet film, and as afurther example decrease 30% for a 20 μm wet film.

The evaporation of the solvent from the wet film can cause a change inviscosity behavior to pseudoplastic, which can be beneficial to achievea precision SLML 14. The dynamic viscosity of the deposited first andsecond SLML 14, 14′, after any solvent has been evaporated, can rangefrom about 10 cP to about 3000 cP, for example from about 20 cP to about2500 cP, and as a further example from about 30 cP to about 2000 cP.When evaporating the solvent, if present, from the wet film there can bean increase in viscosity to the pseudoplastic behavior. Thepseudoplastic behavior can allow for self-leveling of the wet film.

In an aspect, the method can include evaporating the solvent present inthe wet film using known techniques. The amount of time required toevaporate the solvent can be dependent upon the speed of theweb/substrate and the dryer capacity. In an aspect, the temperature ofthe dryer (not shown) can be less than about 120° C., for example lessthan about 100° C., and as a further example less than about 80° C.

The wet film deposited using a liquid coating process can be cured usingknown techniques. In an aspect, the wet film can be cured using a curingagent utilizing at least one of an ultraviolet light, visible light,infrared, or electron beam. Curing can proceed in an inert or ambientatmosphere. In an aspect, the curing step utilizes an ultraviolet lightsource having a wavelength of about 395 nm. The ultraviolet light sourcecan be applied to the wet film at a dose ranging from about 200 mJ/cm²to about 1000 mJ/cm², for example ranging from about 250 mJ/cm² to about900 mJ/cm², and as a further example from about mJ/cm² to about 850mJ/cm².

The wet film can crosslink by known techniques. Non-limiting examplesinclude photoinduced polymerization, such as free radicalpolymerization, spectrally sensitized photoinduced free radicalpolymerization, photoinduced cationic polymerization, spectrallysensitized photoinduced cationic polymerization, and photoinducedcycloaddition; electron beam induced polymerization, such as electronbeam induced free radical polymerization, electron beam induced cationicpolymerization, and electron beam induced cycloaddition; and thermallyinduced polymerization, such as thermally induced cationicpolymerization.

A SLML 14, 14′ formed using the liquid coating process can exhibitimproved optical performance, i.e., be a precision SLML. In someexamples, a precision SLML 14, 14′ can be understood to mean a SLMLhaving less than about 3% optical thickness variation, about 5% opticalthickness variation, or about 7% optical thickness variation across thelayer.

In an aspect, the liquid coating process can include adjusting at leastone of speed from about 5 to about 100 m/min and a coating gap fromabout 50 μm to about 100 μm to deposit a wet film from about 2 μm to 10μm of the selective light modulator layer with a predetermined thicknessfrom about 500 nm to about 1500 nm. In a further aspect, the process caninclude a speed of 30 m/min, a 75 um gap, 10 um wet film, dry filmthickness 1.25 um.

The articles 10 described above and, for example, illustrated in theFigures can be further described by the following examples. In anexample, an article 10 can include a selective light modulator layer 14can include an alicyclic epoxy resin host using a solvent dye as theSLMM, and the reflector lay 16 can include aluminum.

In an example, the article 10 can include a first SLML 14 including analiphatic epoxy resin host using a diketopyrrolopyrrole insoluble reddye as the SLMP, and the reflector layer 16 can include aluminum.

In an example, article 10 can include a first SLML 14 including anacrylate oligomer resin host using white pigment (Titania) as the SLMP.

In an example, an article 10 can include the SLML 14 including anacrylate oligomer resin host using black IR transparent pigment as theSLML, and the reflector layer 16 can include aluminum.

In an example, an article 10 can include an azimuthal layer 12 includinga surface selective dye staining for both a first SLML 14 and areflector layer 16 (metal and non-metal) sides. In an aspect, thearticle 10 can further include a functional layer on a second surface ofboth of a first selective light modulator layer 14 and a secondselective light modulator layer 14′ to prevent the dye staining of theexternal surfaces (the second surface of the SLML 14, 14′).

In an example, an article 10 can include the azimuthal layer 12including selective decorative anodizing of metal on the perimeter ofthe pigment flake.

In an example, an article 10 can include the azimuthal layer 12including selective dye staining of the first and/or second lightmodulator layer 14, 14′.

In an example, an article 10 can include the azimuthal layer 12including two distinct colors, one by selective decorative anodizing ofmetal, one by selective dye staining of the first selective lightmodulator layer 14 and/or the reflector layer 16.

From the foregoing description, those skilled in the art can appreciatethat the present teachings can be implemented in a variety of forms.Therefore, while these teachings have been described in connection withparticular embodiments and examples thereof, the true scope of thepresent teachings should not be so limited. Various changes andmodifications can be made without departing from the scope of theteachings herein.

This scope disclosure is to be broadly construed. It is intended thatthis disclosure disclose equivalents, means, systems and methods toachieve the devices, activities and mechanical actions disclosed herein.For each device, article, method, mean, mechanical element or mechanismdisclosed, it is intended that this disclosure also encompass in itsdisclosure and teaches equivalents, means, systems and methods forpracticing the many aspects, mechanisms and devices disclosed herein.Additionally, this disclosure regards a coating and its many aspects,features and elements. Such a device can be dynamic in its use andoperation, this disclosure is intended to encompass the equivalents,means, systems and methods of the use of the device and/or opticaldevice of manufacture and its many aspects consistent with thedescription and spirit of the operations and functions disclosed herein.The claims of this application are likewise to be broadly construed. Thedescription of the inventions herein in their many embodiments is merelyexemplary in nature and, thus, variations that do not depart from thegist of the invention are intended to be within the scope of theinvention. Such variations are not to be regarded as a departure fromthe spirit and scope of the invention.

What is claimed is:
 1. An optical device, comprising: a reflector layerincluding a metal and having a first surface, a second surface oppositethe first surface; a third surface, and a fourth surface opposite thethird surface; a first selective light modulator layer external to thefirst surface of the reflector layer; and an azimuthal modulator layerpresent on at least one of the third surface and the fourth surface ofthe reflector layer; wherein the azimuthal modulator layer includes themetal chemically converted to a colored metal compound.
 2. The opticaldevice of claim 1, wherein the first selective light modulator layerprovides a first color attribute to the optical device.
 3. The opticaldevice of claim 1, further comprising a second selective light modulatorlayer external to the second surface of the reflector layer.
 4. Theoptical device of claim 1, wherein the azimuthal modulator layerprovides a second color attribute to the optical device.
 5. The opticaldevice of claim 4, wherein the second color attribute is different froma first color attribute.
 6. The optical device of claim 2, wherein thefirst color attribute is present at a first viewing angle.
 7. Theoptical device of claim 4, wherein the second color attribute is presentat a second viewing angle.
 8. The optical device of claim 7, wherein thesecond viewing angle is different from a first viewing angle.
 9. Theoptical device of claim 1, wherein the reflector layer includes acolored material.
 10. A composition comprising the optical device ofclaim 1 and a liquid medium.
 11. The optical device of claim 1, whereinthe azimuthal modulator layer includes at least one of pigments andorganic dyes.
 12. A method of manufacturing an optical device,comprising: depositing on a substrate a reflector layer including ametal having a first surface, a second surface opposite the firstsurface, a third surface, and a fourth surface opposite the thirdsurface; depositing on the first surface of the reflector layer a firstselective light modulator layer; and providing an azimuthal modulatorlayer on at least one of the third surface and the fourth surface of thereflector layer, wherein the azimuthal modulator layer includes themetal chemically converted to a colored metal compound.
 13. The methodof claim 12, further comprising depositing a second selective lightmodulator layer between the substrate and the reflector layer.
 14. Themethod of claim 12, wherein the azimuthal modulator layer inhibitscorrosion of the reflector layer.
 15. The method of claim 12, whereinthe first selective light modulator layer provides a first colorattribute and the azimuthal modulator layer provides a second colorattribute different from the first color attribute.
 16. The method ofclaim 12, wherein the azimuthal modulator layer includes pigments andorganic dyes.